The application of genetic engineering to the murine cardiovascular system has yielded considerable information regarding the signaling pathways and regulation of the heart. Previously, there had been limited information regarding the relevance of these alterations to cardiovascular physiology. The advent of miniaturized electronics and improved microsurgical techniques has enabled the assessment of the physiologic effects of these genetic manipulations and has extended the understanding of the importance of these alterations. The purpose of the Hemodynamic Laboratory Core is to provide the Investigators of each Project the means by which the physiologic and pathophysiologic importance of their specific genetic interventions can be investigated. Methods to be used include studies of the ex vivo heart, in vivo cardiac catheterization, in vivo echocardiography, and application of these techniques to a rodent model of myocardial infarction and heart failure.